The following disclosure is based on Japanese Patent Application No. 2001-249348, filed on Aug. 20, 2001, which is incorporated into this application by reference.
This invention relates to a film transfer apparatus and more particularly to an improvement in a non-return mechanism for a take-up reel of a film transfer apparatus of a type which is formed by combining a cartridge unit and a case body with each other. A feed reel and a take-up reel around which a transfer tape adapted to be reversed on a transfer head is wound are supported by the apparatus so that the two reels can be rotated relatively and smoothly irrespective of an increase and a decrease in the amounts of the transfer tape wound around the reels.
FIG. 8 is a perspective view of a typical conventional film transfer apparatus, and FIG. 9 an exploded view in perspective of the film transfer apparatus shown in FIG. 8.
The conventional film transfer apparatus 01 is provided with a cartridge unit 01 and a case body 03.
The cartridge unit 02 serves as a cover and is slightly laterally elongated, i.e., elliptic in a front elevation. The cartridge unit 02 is provided at one lateral end of a front side-opened, flat, case member 04 thereof with a cutout hole 05 as a window-like hole, from which a transfer head 06 is projected. In the case member 04, a feed reel 07 and a take-up reel 08 are provided laterally spaced from each other. A portion of a coiled transfer tape 09 wound around the feed reel 07 and drawn out therefrom is reversed at a tip 06a of the transfer head 06 and then taken up around the take-up reel 08.
The case body 03 is formed of a front-side opened, flat case member 010 having substantially the same contour in a front elevation as the cartridge unit 02, but the contour of the case body being slightly larger than that of the cartridge unit. The case member 010 is provided at one lateral end thereof with a cutout hole 011 as a window-like hole. In the interior of the case member, a feed gear 012 and a take-up gear 013 are arranged laterally spaced from each other, both meshing with an intermediate gear 014. These gears 012, 013 are adapted to be rotated in the same direction.
The positions, shapes and sizes of the two cutout holes 05, 011 are determined so that the cutout holes are aligned with each other when the cartridge unit 02 and the case body 03 are engaged with each other as will be described later.
To obtain the assembled film transfer apparatus 01, the cartridge unit 02 and case body 03 are disposed the open sides thereof opposite to each other, and a shaft 015 in the center of the feed gear 012 is inserted into a shaft cylinder 016 in the center of the feed reel 07 with a shaft 017 in the center of the take-up gear 013 into a shaft cylinder 018 in the center of the take-up reel 08. The transfer head 06 projects out from the cutout holes 05, 011 of the mutually aligned cartridge unit 02 and case body 03, and the cartridge unit 02 and case body 03 are thereby engaged with each other for forming one body.
In this film transfer apparatus 01, the shaft 015 in the center of the feed gear 012 and the shaft 017 in the center of the take-up gear 013 are inserted into the shaft cylinders 016, 018 of the feed reel 07 and take-up reel 08 respectively. The film transfer apparatus is operated as follows.
When the film transfer apparatus is moved rightward in FIG. 8 as the transfer head 06 is pressing against a surface of a sheet, the transfer tape 09 slides on the tip 06a of the transfer head 06 and a portion of the transfer tape 09 which is wound like a coil around the feed reel 07 is turned. A turning force is transmitted to the feed gear 012 via the shaft 015 inserted in the shaft cylinder 016 of the feed reel 07, and further to the take-up gear 013 operatively connected to the feed reel 07.
The turning force is then transmitted to the take-up reel 08 via the shaft 017 in the center of the take-up gear 013 and the shaft cylinder 018 in which the shaft 17 is inserted.
Owing to the turning force thus transmitted, the portion of the coiled transfer tape 09 on the feed reel 07 which is drawn therefrom is reversed at the tip 06a of the transfer head 06 and then taken up around the take-up reel 08.
To be precise, in an initial stage of a film transfer operation, the diameter of the coiled transfer tape 09 on the feed reel 07 is large, and that portion thereof taken up around the take-up reel 08 is small. However, as the transfer tape is used, the diameters of the coiled transfer tape on the feed reel 07 and take-up reel 08 are gradually reversed.
A compensation of the differing rotation ratio of the feed reel 07 to the take-up reel 08 is made by interposing a resistance member, for example, a suitable spring and a ring-shaped material between the shaft cylinder 016 of the feed reel 07 and the shaft 015 in the center of the feed gear 012, or between the shaft cylinder 018 of the take-up reel 08 and the shaft 017 in the center of the take-up gear 013 so that the shafts 015, 017 and shaft cylinders 016, 018 are rotated relatively with a low resistance generated therebetween.
In order that an operator cannot move the film transfer apparatus reversely, a reverse rotation preventing mechanism is usually provided on the take-up reel 08 so that the transfer tape 09 is not drawn from the take-up reel 08, and shaking of the apparatus during a transfer tape operation does not cause the transfer tape 09 on the take-up reel 08 to be turned back.
As a device for preventing a reverse rotation of the take-up reel 08, a ratchet mechanism is disclosed, for example, in the Japanese patent laid-open document No. 104563/1997.
Namely, in the conventional apparatus according to FIGS. 8 and 9, a reverse rotation preventing annular toothed member 019 coaxial with the take-up gear 013 combined in one body with the shaft 017 supporting the take-up reel 013, and an elastic plate type claw member 020 directed from a suitable portion of the take-up gear 013 toward the annular toothed member 019 are provided on an inner surface of the case body 03, the claw member 020 being engaged with the annular toothed member 019 in a reverse rotation preventing manner.
However, when the annular toothed member 019 or the plate type claw member 020 of this conventional reverse rotation preventing mechanism are worn out or bent as these parts are used, resulting in that the functions thereof becoming incomplete, it is necessary to remove the cartridge unit 02 from the case body 03, renew the case body 03 combined with the annular toothed member 019 in one body, or the take-up gear 013 provided with the claw member 020, and then put the case body 03 and cartridge unit 02 together again.
Such operations are troublesome and need delicate carefulness, and various parts scatter and move. Therefore, a user cannot carry out such operations easily at all.
The present invention has been made to overcome the above-mentioned inconveniences. Namely an object of the invention is to provide a film transfer apparatus having a mechanism which is adapted to prevent a reverse rotation of a transfer tape-wound take-up reel and includes a check claw and check teeth, in which the check claw and one of the check teeth can be engaged with each other firmly and reliably. Another object of the invention is to provide a film transfer apparatus in which only the check claw member-carrying parts need to be renewed which can be done easily by a simple operation when the check claw should be broken or deformed resulting in that the functions thereof become incomplete.
These and other objects are solved in accordance with the present invention by a film transfer apparatus which comprises a cartridge unit and a case body adapted to be combined with said cartridge unit, and including a feed reel and a take-up reel supported on the case body, around which a transfer tape adapted to be reversed on a transfer head is wound, these reels can be rotated relatively and smoothly irrespective of an increase and a decrease in the amounts of the transfer tape wound around the two reels, and a reverse rotation preventing mechanism. Said mechanism comprises a check pin inserted from the outer side of the cartridge unit into a cylindrical retainer shaft on which the take-up reel is rotatably mounted, combined in one body rotationally with the take-up reel, and engaged in a reverse rotation preventing manner in a tightly winding direction with respect to the cartridge unit.
According to an embodiment of the invention the check pin can be provided on an outer circumferential portion of a free end thereof with a slip-off preventing projection capable of being engaged with a shaft hole of the take-up reel supported rotatably on the case body.
According to another embodiment of the invention an outer circumferential surface of the check pin and an inner circumferential surface of the shaft hole of the take-up reel can be provided with axially extending locking ribs engageable with each other in a rotational direction thereof.
Still according to another embodiment of the invention the cylindrical retainer shaft on which the take-up reel in the cartridge unit is rotatably mounted can be provided on an inner circumferential surface thereof with teeth extending in one circumferential direction thereof, the check pin being provided at the portion of an outer circumferential surface thereof which is opposed to the teeth with a check or locking claw engageable with one of the teeth in a predetermined direction only.
Finally according to another embodiment of the invention the check pin can be withdrawn from the cartridge unit by a screw driver.